title: Weight corrected percentiles for blood vessel diameters used in flow measurements in preterm infants.
abstract: BACKGROUND
  Blood flow measurements are an integral part of haemodynamic assessment of the newborn infant. Most variability of Doppler derived blood flow is caused by diameter measurements. Population based percentiles of diameter measurements would be useful for training of clinicians undertaking blood flow measurements and allow rapid identification of outliers.
  
  
  METHODS
  Diameter measurements of pulmonary valve annulus, ascending aorta and the superior vena cava using standardised methodology were collected retrospectively from 9 prospective studies on transitional haemodynamics in preterm infants. Data were analysed to calculate weight corrected percentiles of diameters used for blood flow measurements.
  
  
  RESULTS
  We analysed 2870 measurements in 694 preterm infants less than 1750 g. The median gestational age was 27 weeks (range 23 to 34 weeks) and the median time of measurement was 22 h after birth (range 0.5 h to 70 days). 76% of measurements were performed while the infant received mechanical ventilation and 20% received cardiovascular support. Mean diameters increased with weight and standard deviations were comparable over the weight range.
  
  
  CONCLUSIONS
  Data from this large combined series provide a reference range for blood vessel diameters in the population most often measured. The data permits recognition of outliers and could be used to trigger review of measurements that fall outside the normal range.
authors.affiliation: Department of Newborn Care, John Hunter Children's Hospital and University of Newcastle, NSW, Australia. Electronic address: koert.dewaal@hnehealth.nsw.gov.au.
authors.forename: Koert
authors.initials: K
authors.lastname: de Waal
authors.forename: Martin
authors.initials: M
authors.lastname: Kluckow
authors.forename: Nick
authors.initials: N
authors.lastname: Evans
mesh_terms: D001808:Blood Vessels / Q000033:anatomy & histology*; D001835:Body Weight / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D012015:Reference Standards; D012039:Regional Blood Flow / Q000502:physiology*; D012189:Retrospective Studies
keywords: Cardiac output; Echocardiography; Newborn